The invention relates to improvements in mechanisms which can be used to releasably lock a mobile first component in a predetermined position relative to a second component. More particularly, the invention relates to improvements in mechanisms which can be utilized with advantage to releasably lock pivotable and/or otherwise movable sashes in door- or window frames.
It is known to provide a door or a window with a mechanism which serves to releasably lock a mobile component (such as the sash of a casement window or the sash of a door and hereinafter called sash) to a second component (e.g., to a door frame or a window frame and hereinafter called frame) by manipulating a knob, a lever or another suitable handle in order to engage one or more female or male (first) locking elements on the sash with one or more male or female (second) locking elements on the frame. The handle can be provided on the sash and the first locking elements are then displaced by the handle when the sash assumes a closed position in which the second locking elements (on or in the frame) are supposed to be ready for engagement by the first locking elements. Such mechanisms operate quite satisfactorily if the sash carries a single first locking element which can engage a single second locking element on or in the frame. However, the situation is quite different if the sash carries a number of spaced apart first locking elements each of which is to engage a discrete second locking element, for example, when the sash is to be locked to its frame at a large number of locations spaced apart from each other along the entire periphery, or along a large portion of the periphery, of the sash. In such instances, the sash can include one or more elongated motion receiving parts, e.g., in the form of bars, which are coupled to the handle and carry a large number of pins or otherwise configurated (first) locking elements each of which must ultimately engage a discrete second locking element on the frame. For example, the first locking elements can constitute pins or analogous followers which are to engage discrete ramps, cams or like parts on the frame in response to actuation of the handle while the sash is maintained in a closed position. When the manipulation of the handle in a direction toward locking of the sash to the frame (while the sash is maintained in the closed position) is completed, each first locking element forms with the complementary second locking element a discrete lock which fixedly secures the corresponding portion of the sash to the adjoining portion of the frame. It is immaterial whether the handle and the motion receiving part(s) are mounted on the sash or on the frame.
The motion receiving elements can include bars or strips which are reciprocably mounted in grooves provided therefor in the sash or in the frame; this ensures that the distance between the handle and that first locking element which is remotest from the handle is a multiple of the distance of the handle from the nearest first locking element. The second locking elements are or can be mounted on or in the frame in such a way that the distance between the handle and the second locking element nearest to the handle is half the distance of the next second locking element and so forth. When the handle is manipulated to lock the sash to the frame, all of the first locking elements are supposed to simultaneously engage the respective second locking elements. However, this is possible only if each first locking element is properly positioned relative to the respective second locking element when the movement (e.g., pivoting) of the sash to the closed position (relative to the frame) is completed. Such situation is not likely to arise if the sash carries a substantial number of first locking elements and if the frame carries an equally large number of second locking elements. The reason is that the frame and/or the sash is likely to undergo at least some deformation for any one of a number of different reasons, e.g., due to thermally induced expansion or contraction, due to excessive stressing and resulting deformation and/or for other reasons.
If at least one of the first locking elements does not accurately register with the associated second locking element, the entire mechanism becomes inoperative because the handle cannot be moved away from a predetermined first position which it must assume in order to permit pivoting and/or other movements of the sash to or from the closed position. Furthermore, if a first locking element is caused to assume an improper position relative to the adjacent second locking element in response to movement of the handle and of the motion receiving element or elements toward locking position, the mechanism is likely to break, to cause a pronounced deformation of one or more of its parts, or to develop a substantial clearance between two or more neighboring portions of the sash and frame.
The likelihood of improper positioning of first locking elements relative to the adjacent second locking elements is especially pronounced if the door or window embodying the sash and the frame therefor is relatively large so that at least some of the first and second locking elements are located at a considerable distance from the handle. Thus, one or more first locking elements which are nearest to the handle are likely to be properly aligned with the corresponding second locking elements; however, a third, fourth, etc. first locking element is much less likely to be adequately aligned with the third, fourth, etc. second locking element when the sash is held in the closed position but is yet to be locked to the frame. This necessitates manual depression of selected portions of the sash (namely the portions remote from the handle) to the fully closed position or positions before the handle can be manipulated in order to lock the sash to the frame. In the absence of such undertaking (to move the entire sash to its closing position), the operator is unable to manipulate the handle and is likely to leave the sash unlocked or to damage the sash, the frame and/or the locking mechanism. If the entire sash does not assume its closed position at the time the handle is manipulated in a sense to lock the sash to the frame, one or more first locking elements are bound to strike portions of the adjacent second locking elements, the nonaligned first locking elements are bound to prevent full movement of the handle to an end position in which the sash is locked to the frame; or the nonaligned first locking elements are free to move along the adjacent second locking elements but not to positions which are required to lock the corresponding portions of the sash and frame to each other; or the mechanism including the handle, the motion receiving element or elements and/or the first and/or second locking elements is damaged or destroyed; and/or certain first locking elements and the corresponding second locking elements cooperate to widen the gap between the sash and the frame when the movement of the handle to a locking position is completed.
Manual depression of a single deformed portion of a sash (in order to move such portion to the closed position) is conceivable (i.e., possible) under certain circumstances, namely when the manual depression is to be carried out by a grown person and does not necessitate the application of a substantial force such as is not expected from a convalescent, a senior citizen and/or a lady. However, even a very strong person cannot ensure that the entire sash is moved to the closed position if two or more spaced apart portions of the sash are to be depressed while the sash portion adjacent the handle is already maintained in the closed position. In other words, it is then necessary that the person attempting to close and lock the sash seek assistance from at least one other person. This is not only cumbersome but also impossible if another person is not available to assist the operator of the door or window embodying one or more frames and an equal number of sashes.